What is Cytauxzoonosis in Cats?
Cytauxzoonosis is a disease in cats, primarily spread through tick bites. It's caused by the single-celled parasite Cytauxzoon felis, which invades a cat's blood cells.
These cells enlarge upon infecting the white blood cells linked to the immune system. This enlargement can lead to blockages in the blood vessels throughout the feline body, causing widespread inflammation and potential harm to various tissues and organs. Additionally, when the parasite infiltrates red blood cells, it can trigger anemia, exacerbating tissue and organ damage due to insufficient oxygen.
This ailment has been detected in multiple regions worldwide, including South America, Europe, Asia, and the US. Within America, Cytauxzoon felis predominantly appears in Central, South-central, Southeastern, and mid-Atlantic zones. The peak period for diagnosing Cytauxzoonosis tends to be between April and September, aligning with the prevalence of ticks.
The US first documented cases of Cytauxzoonosis in 1976, labeling it an urgent health concern. Although it's relatively rare in house cats, astonishingly, in areas where the disease is endemic, it has been found in nearly 79% of wild feline populations.
Symptoms of Cytauxzoonosis in Cats
Symptoms of cytauxzoonosis in felines begin subtly but can escalate to a severe, potentially fatal condition. Usually, signs emerge 5 to 14 days post-infection.
Frequent manifestations include:
- Enlarged lymph nodes
- Increased heart rate and/or respiratory rate
- Abdominal pain
Causes of Cytauxzoonosis in Cats
Cytauxzoon felis is transmitted via tick bites, primarily from the lone star tick (Amblyomma americanum) and the American dog tick (Dermacentor variabilis). This disease is often dubbed "bobcat fever" because the bobcat (Lynx rufus) is its primary host. Interestingly, most bobcats don't display any symptoms; instead, they silently spread the disease to local ticks without showing signs of being affected.
Subsequently, these infected ticks can transfer the parasite to other felines, whether wild or domesticated. Regrettably, this disease can be fatal for many cat species. Direct cat-to-cat transmission isn't possible; a cat has to be bitten by an infected tick to contract the disease. Merely consuming a tick won't result in infection; the tick has to bite the feline.
It's worth noting that cytauxzoonosis is exclusive to the feline family. Humans and dogs remain unaffected by it.
Diagnoses Of Cytauxzoonosis in Cats
Upon visiting your veterinarian, they will perform a comprehensive physical check-up, looking for symptoms like fever, yellowing of the skin (jaundice), and sensitivity in the abdomen. Sharing details about recent travels or encounters with ticks can aid your vet in assessing the possibility of cytauxzoonosis. They suggest a complete blood profile, blood chemistry analysis, and a urinalysis to establish a foundational assessment.
A conclusive diagnosis is typically reached by spotting the parasitic entity through microscopic observation, either from a blood sample placed on a slide or an organ sample obtained via fine-needle aspiration, such as from the liver or spleen. Under the microscope, Cytauxzoon felis manifests as a structure resembling a signet ring within the red blood cells. It resembles and sometimes can be mistaken for, other parasitic entities like Mycoplasma hemofelis or Babesia felis.
In the initial phases of the disease, this parasite isn't detectable in the bloodstream. If there's suspicion of cytauxzoonosis, it's advised to repeat the test within a 12 to 24-hour window.
To verify the disease, a polymerase chain reaction test can be conducted using either blood or tissue samples to detect the presence of the Cytauxzoon felis parasite.
Treatment of Cytauxzoonosis in Cats
Prompt diagnosis and proactive treatment are essential for effectively handling cytauxzoonosis. Almost all domestic cats succumb to the disease without treatment, but timely and rigorous intervention can reduce this fatality rate to about 40%.
The affected cats need hospitalization to receive IV fluids, which help counteract dehydration and rectify electrolyte imbalances. Supportive care measures like medications for nausea or pain, blood transfusions, and dietary support (potentially using feeding tubes and appetite enhancers) are also initiated. The preferred treatment method for combating Cytauxzoon felis involves using antiprotozoal drugs like atovaquone paired with azithromycin, which has a 50-60% survival rate.
Recovery of Cytauxzoonosis in Cats
Cytauxzoonosis poses a lethal threat to cats, with around 60% surviving even after receiving intensive treatment. Those who don't make it often pass away within the initial 24 hours of their ICU admission. Most affected cats undergo hospitalization for 7 to 10 days, during which they're provided IV fluids, essential supportive care, and a regimen including antiprotozoal drugs (specifically Atovaquone and Azithromycin).
Cats that make it through this ordeal typically recuperate over two to three weeks and can anticipate resuming their regular routines. However, it's crucial to note that most cats that overcome the acute phase of cytauxzoonosis may still harbor the infection, even though they exhibit no apparent symptoms. While they won't require ongoing medication, they will perpetually carry the Cytauxzoon felis infection, making them potential carriers for ticks, akin to the bobcat, its natural host.
Given ticks' pivotal role in disseminating cytauxzoonosis, adopting a regular flea and tick prevention routine is indispensable. For those residing in regions where cytauxzoonosis is prevalent, confining cats indoors can effectively reduce the chances of exposure and subsequent risk.